A spokesman for former US president George HW Bush has issued an apology after erroneously issuing a statement of condolence saying South African anti-apartheid hero Nelson Mandela had died.

Bush spokesman Jim McGrath later explained he circulated a prepared statement expressing Mr Bush's sorrow at the "death" of the former South African president after misreading a Washington Post news alert about Mr Mandela's discharge from hospital.

"The 41 stmnt sent this morning was the result of my mis-reading the header on the WaPo news flash. Stupid mistake by me. Apologies to all," Mr McGrath wrote on his Twitter account.

"The mistake was mine and not the Bushes," he added later.

Mr Bush's statement earlier described Mr Mandela as "one of the greatest believers in freedom we have had the privilege to know" hailing him as "a man of tremendous moral courage who changed the course of history in his country."

The 41 stmnt sent this morning was the result of my mis-reading the header on the WaPo news flash. Stupid mistake by me. Apologies to all.

Following his release from hospital yesterday, a statement from the office of current South African president Jacob Zuma confirmed the 95-year-old had returned to his Johannesburg home, where he will continue to recover.

"Madiba's condition remains critical and is at times unstable," the presidency said, referring to Mr Mandela by his clan name.

"Nevertheless, his team of doctors are convinced that he will receive the same level of intensive care at his Houghton home that he received in Pretoria.